Grade 12 Biology Unit 2: Microorganisms

🚨 Highly frequent in the ESSLCE exam.

This unit 2 explores the structure, classification, and importance of microorganisms including bacteria, archaea, fungi, protozoa, and viruses. You will also study diseases caused by microorganisms, methods of disease prevention, and the role of microorganisms in industry, the environment, and daily life.

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Chapter 2.1 – Eubacteria

• Structure of Bacterial Cell – components of prokaryotic cells.
• Bacterial Shapes – cocci, bacilli, spirilla, and vibrio.
• Nutritional Types of Bacteria – autotrophs and heterotrophs.
• Reproduction of Bacteria – asexual (binary fission) and sexual methods.

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Chapter 2.2 – Archaea

• Beneficial aspects of archaea.
• Physical and environmental factors influencing archaeal growth.

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Chapter 2.3 – Fungi

• General characteristics of fungi.
• Ecology and classification of fungi.
• Reproduction in fungi (asexual and sexual).
• Economic importance of fungi.

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Chapter 2.4 – Protozoa

• Common diseases caused by protozoa (e.g., malaria, amoebiasis).

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Chapter 2.5 – Viruses

• Characteristics of viruses.
• Viral symmetry and structural organization.
• Classification of viruses.

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Chapter 2.6 – Normal Microbiota

• Role of beneficial microorganisms in the human body.

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Chapter 2.7 – Modes of Disease Transmission and Prevention

• Routes of transmission: direct, indirect, airborne, vector-borne.
• Preventive measures: sanitation, vaccination, safe food practices.

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Chapter 2.8 – Uses of Microorganisms

• In food and beverage production (bread, yogurt, alcohol).
• In medicine (antibiotics, vaccines).
• In environmental balance (decomposition, nitrogen fixation).

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Chapter 2.9 – Controlling Microorganisms

• Physical methods (heat, radiation).
• Chemical methods (disinfectants, antiseptics, antibiotics).

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Chapter 2.10 – Renowned Microbiologists in Ethiopia

• Contributions of Ethiopian scientists to microbiology.

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Learning Outcomes

By the end of this unit 2, you will be able to:

• State the characteristics of microorganisms.
• Explain the different groups of microorganisms.
• Describe diseases caused by bacteria, fungi, protozoa, and viruses.
• Explain the role of microorganisms in industry, environment, and health.
• Discuss disease prevention and treatment mechanisms.
• Recognize the contributions of Ethiopian microbiologists.